<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>待办任务列表</title>
    <script src="https://unpkg.com/vue@3/dist/vue.global.js"></script>
</head>
<body>
    <div id="Application">
        <!-- 输入框元素，用来新建待办任务 -->
        <form @submit.prevent="addTask">
            <span>新建任务</span>
            <input 
            v-model="taskText"
            placeholder="请输入任务..."
            />
            <button>添加</button>
        </form>
        <!-- 有序列表，使用v-for来构建 -->
        <ol>
            <li v-for="(item, index) in todos">
                {{item}}
                <button @click="remove(index)">
                    删除任务
                </button>
                <hr/>
            </li>
        </ol>
    </div>
    <script>
        const App = {
            data() {
                return {
                    // 待办任务列表数据
                    todos:[],
                    // 当前输入的待办任务
                    taskText: ""
                }
            },
            methods: {
                // 添加一条待办任务
                addTask() {
                    // 判断下输入框是否为空
                    if (this.taskText.length == 0) {
                        alert("请输入任务")
                        return
                    }
                    this.todos.push(this.taskText)
                    this.taskText = ""
                },
                // 删除一条待办任务
                remove(index) {
                    this.todos.splice(index, 1)
                }
            }
        }
        Vue.createApp(App).mount("#Application") 
    </script>
</body>
</html>